Polymers of halogen-containing ethylenically unsaturated monomers, such as the vinyl or vinylidene halides, are often prepared as aqueous latices or emulsions in which form they may be conveniently used as coatings, adhesives, paint bases, binders for non-woven fabrics, coatings for woven fabrics including fabrics prepared from natural, synthetic, mineral or glass fibers and in various other types of applications. In many instances, particularly where they are being considered for use in building interiors or in uses requiring their prolonged exposure to high temperatures, it is highly desirable and advantageous that these lactices should display enhanced fire or flame retardant properties and color stability so that they may be safely employed in place of more costly materials. Moreover, it is highly desirable and advantageous that these latices when applied to flexible substrates, should impart a desirably soft "hand" to said substrates.
Prior attempts to provide fire retardant, film-forming vinyl or vinylidene halide polymer latices have involved the preparation of various polymeric compositions including copolymer latices of vinyl halides and alkyl acrylates, copolymer latices of vinyl halides and vinylidene chloride and polyvinyl halide latices containing an extraneously added phosphate ester plasticizer. Other attempts have involved the use of interpolymers of bis(.beta.-chloroethyl) vinyl phosphonate with lower alkyl acrylates or methacrylates and acrylic or methacrylic nitriles. These interpolymers could additionally optionally include vinyl halides or vinylidene halides. Still other attempts have involved interpolymerization of vinylidene halide monomers with carboxylic acid monomers and N-alkylol acrylamide monomers. These latter interpolymers could optionally include other polymerizable comonomers such as esters of acrylic acid or methacrylic acid, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide or methacrylamide, styrene or bis(.beta.-haloalkyl) vinyl phosphonates. However, despite the many and varied attempts to obtain a completely satisfactory polymeric latex, none of the above-described approaches has proven to be completely satisfactory as the resultant products are found, in many cases, to be lacking in either sufficient fire retardancy, color stability, mechanical stability, ultraviolet stability, softness of the polymers or the products are subject to the gradual loss of their extraneously added phosphate plasticizers.
Accordingly, it is an object of this invention to provide novel, fire retardant halogen-containing vinyl polymer additives which may be used in a variety of coating, binding, and laminating applications and which are characterized by their essentially complete freedom from the various disadvantageous properties heretofore associated with this type of product.
It is another object of this invention to provide a novel class of polymers in the form of aqueous emulsions or latices which are particularly useful, as additives, for preparing fire retardant, polymer compositions which are in the form of aqueous solutions, suspensions or, most preferably, emulsions.
It is a further object of this invention to provide solid polymeric fire retardant additives or blends by drying or coagulating or co-coagulating the polymer emulsions or latcies of this invention by themselves or as blends with other polymeric emulsions or latices. The solid polymeric additives of the present invention can also be blended with ordinarily flammable solid polymers to give flame retardant polymeric blends.
It is still another object of the present invention to provide a novel class of polymers in the form of aqueous emulsions or latices which are particularly useful as binders for non-woven fabrics and coating for woven fabrics prepared from natural, synthetic, mineral, glass fibers or mixtures thereof.
Various other objects and advantages of this invention will be apparent from the disclosure thereof which follows hereinafter.